I'm right in the middle of your low handicap category. It's hard to avoid thinking only of the great shots and guessing what a reasonable average for me would be, but here goes:
From 100 yds. out, I'd guess my average is about 20 feet at best, so let's say a 7 yd. radius. 100 yds. for me is my 48 degree wedge. I feel great if I have a 10 foot putt or less, OK inside 20 feet, and not too bad as long as I hit the green or can putt through a little fringe.
Keep in mind that I'm quite capable of blading it into the next county or chunking it into the trap or the pond. A shot like that would significantly distort the calculation of my average distance from the pin, so when I say a 7 yd. radius, I'm thinking more of a median distance than a mean distance. (I apologize for the statistical detail.)
With my driver, I'm happy if I hit the fairway. My home course has narrow fairways with a lot of tight landing areas and out of bounds threats. I haven't tracked it for a while, but the last time I checked a bad day was hitting less than 50% of the fairways and a great day was hitting 12 of 14, so about 85%. Average was closer to 60% or 65%.
I'm not sure what that means about shot radius, but given the width of my fairways and my hit rate, a 15 yard radius is a very good day for me. I'd hate to guess at my average driver dispersion. I'd probably be way off and it would also be depressing. It's hard to get an accurate figure for that drive into someone's back yard or the one that nails a buck on the other side of the game fence. I've done both.
Finally, if I'm on the range hitting shot after shot under the same conditions, I can get a pretty tight pattern with most clubs. It's when I've got 1 shot at it with changing lies, wind, elevation changes, and my own mental gyrations for each shot that things get interesting.